Holding tank systems: Drop 2 tablets through toilet opening into waste holding tank prior to use or after emptying tank. Flush toilet to add water to tank.Portable toilets: Drop 2 tablets into waste holding tank through valve opening with a small amount of water to cover tank bottom.Recirculating toilets: Drop 2-4 tablets into initial water charge. 12 Tabs per card.
Not intended for grey water holding tanks.